There are still a ton of differences: contemporary music doesn't have the same divisions of works into movements separate from what appears on an album (you don't generally have covers of entire albums); while a cover of a particular song is a common search, it is far less common to try and find all covers by other artists from a particular artists (i.e. all piano works by Beethoven); and finally, most contemporary music has a single name meanwhile most famous classical works have many (opus/catalogue number, sonata number, nicknames, foreign language names, etc.).

As a bonus, most contemporary music probably also doesn't feature dozens of artists (while the whole orchestra usually isn't listed individually, all the soloists in an opera often are). That said, I think this is one area where apps have improved.